1. Field of the Invention
The present invention relates to communication terminal devices and specifically to communication terminal devices including a UHF-band RFID (Radio Frequency Identification) system and a UHF-band mobile communication system.
2. Description of the Related Art
The UHF-band RFID system provides a longer communication distance than the HF-band RFID system and is capable of collectively reading a plurality of tags. Therefore, the UHF-band RFID system is advantageous in constructing an article management system in which articles are managed based on ID information read from tags attached to the articles.
Particularly, a wireless IC device disclosed in WO 2009/011154 is useful as an RFID tag used in a system for management of various electronic devices in manufacturing processes and/or at product steps. This wireless IC device uses a ground conductor provided in a printed wiring board incorporated in an electronic device as an antenna element, and therefore, it is not necessary to separately provide an antenna element for exclusive use, leading to size reduction of the tag.
In recent years, size reduction and thickness reduction have been demanded of mobile communication terminals such as smartphones, and there is a trend that the area of an incorporated printed wiring board is reduced. Accordingly, the area of the ground conductor provided in the printed wiring board is also reduced. As a result, the RFID tag which uses the ground conductor as the antenna element has difficulty in securing a sufficient communication distance.